1. Field of the Invention
The present invention relates to a method for producing
aluminum-containing members and such aluminum-containing members. More specifically the present invention relates to a method for producing aluminum-containing members to be favorably used in semiconductor-producing devices, liquid crystal-producing devices, etc. and such aluminum-containing members.
2. Related Art Statement
As wirings in the semiconductors and liquid crystal panels become finer, fine workings with dry processings are progressing. With the demand for such fine workings, a halogen-based corrosive gas is used as a film-forming gas or an etching gas for the semiconductors or the like.
On the other hands, it is known that aluminum nitride exhibits high corrosion resistance against such a halogen-based corrosion gas. Therefore, members having aluminum nitride on their surfaces have been used in semiconductor-producing apparatuses, liquid crystal panel-producing apparatuses, etc.
More specifically, there are available powdery aluminum nitride sintered materials, materials in which aluminum nitride is formed on a substrate by using a gas phase growing method such as CVD, and materials in which a surface of aluminum is modified and aluminum nitride is formed thereon.
When aluminum contacts air, its surface is oxidized to form a thin oxidized film. Since this oxidized film is an extremely stable passive phase, the aluminum surface could not be nitrided by a simple nitriding method. Under the circumferences, the following method has been developed to modify the surface of aluminum and form aluminum nitride thereon.
JP-A 60-211,061 discloses a method in which after the inner pressure of the chamber is reduced to a given pressure and hydrogen is introduced thereinto, discharging is effected to heat the surface of a member of such as aluminum to a given temperature, further argon gas is introduced and discharging is effected to activate the surface of the member, and the surface of the aluminum member or the like is ionically nitrided through introducing nitrogen gas.
JP-A 7-166,321 discloses a method in which a nitriding aid made of aluminum powder is contacted with the surface of the aluminum, and since aluminum nitride is formed on the surfaces of aluminum nitride through heating in the nitrogen atmosphere.
However, according to the method described in JP-A 60-211,061, since aluminum nitride is formed by using discharging, the entire device is complicated to raise the cost. Further, it is difficult for this method to members having complicated shapes or large sizes.
Furthermore, according to a method described in JP-A 7-166,321, since a nitriding aid is used, voids exist in a resulting surface layer of aluminum nitride so that denseness is not sufficient. For this reason, it is an actual situation that corrosion resistance against the halogen-based corrosive gas is not sufficient and cannot be said to be practically satisfactory.
Further, if aluminum nitride is formed by sintering, aluminum nitride powder needs to be sintered at a high temperature and the sintered body is difficult to be worked, thereby raising the cost. Further, it was extremely difficult to form members having large sizes or complicated shapes.
In the case that aluminum nitride is formed by CVD process, the producing device and process are complicated and precious, it is also difficult to members having large sizes or complicated shapes.
It is an object of the present invention to provide a method for forming a nitride on a surface of a given substrate in a simple manner and to provide an aluminum-containing member having a high corrosion resistance against a halogen-based corrosive gas.
The present invention relates to a method for producing an aluminum-containing member, comprising the steps of heating a substrate containing at least metallic aluminum in vacuum of not more than 10xe2x88x923 torrs, and forming a nitride in a surface portion of the substrate by heating/nitriding the substrate in a nitrogen atmosphere, continuing with said heating step.
The present invention also relates to an aluminum-containing member comprising a substrate containing at least metallic aluminum, and a nitride in a surface portion of the substrate, wherein the nitride contains at least one element selected from the group consisting of metals of Group 2A, Group 3A, Group 4A and Group 4B in Periodic Table at a higher concentration than that in a metallic aluminum-containing portion in the substrate.
These and other objects, features and advantages of the invention will be appreciated upon reading of the following description of the invention when taken in conjunction with the attached drawings, with understanding that some modifications, variations and changes of the same could be easily made by the skilled person in the art to which the invention pertains.